Fig. 4

Effect of the CRISPR–Cas system in recipient strains on the stability of mobilizable plasmids. a The conjugation frequencies of the targeted conjugative pKPHS2 (p2), the nontargeted mobilizable pKPHS3 (p3) and pRJF293 (pV). The donor strain was K. pneumoniae RJF293-p2-p3 and the recipient strains were K. pneumoniae KpBSI083A and KpBSI083Δcas3H. Detailed data are available in Additional file 6: Table S5. b Schematic of plasmid stability in transconjugants during 13 days of serial passage culture. The plasmid was detected by PCR and antimicrobial susceptibility tests. Plasmids that were retained are indicated by gray squares, while plasmids that were lost are indicated by white squares. Full details of plasmid stability in transconjugants are shown in Additional file 7: Table S6. c The proposed mode of the impact of the CRISPR–Cas system on the dissemination of targeted conjugative plasmids